Duftite-alpha

PbCu(AsO4)(OH)
IMA status
  • Grandfathered
  • Questionable
Also known as
  • Alpha-Duftite
  • α-Duftit
  • α-Duftita

Where it forms, where it's found

3recorded occurrences
Source · OpenStreetMap

Safety & handling

Physical

Hardness
123456789103/ 10 MOHS
  1. 1Talc
  2. 2Gypsum
  3. 3Calcite
  4. 4Fluorite
  5. 5Apatite
  6. 6Orthoclase
  7. 7Quartz
  8. 8Topaz
  9. 9Corundum
  10. 10Diamond
Colour
Green

Optical

Optical type
Biaxial (-)
Refractive index
2.04 – 2.1
Surface relief
Very high
Principal indices
nα 2.04 · nβ 2.08 · nγ 2.1
Dispersion
r < v strong
Michel-Lévy diagramhighlighted lineδ = 0.0600
Attainable Michel-Lévy rangeΔ ∈ [0, t·δmax]600 nm2nd order
Δ = 0Δmax
Thin-section mosaic70 grains · random 3D orientations
PPLpleochroism per grain
XPLindependent extinctions · rotate the stage
Interference simulatorsingle grain · PPL ↔ XPL
PPLpleochroism only · colour blends on rotation
XPLinterference colour · extinct every 90°
Retardation600 nm
Order2nd order
XPL colour

Chemical composition

Constituent elements
Mass composition breakdown
ElementAtoms At. mass g/mol Mass g/molMass share
82PbLeadLead1207.200207.200
48.56%
8OOxygenOxygen515.99979.995
18.75%
33AsArsenicArsenic174.92274.922
17.56%
29CuCopperCopper163.54663.546
14.89%
1HHydrogenHydrogen11.0081.008
0.24%
Total426.671100.00%

Mass share = atoms × atomic mass ÷ molar mass × 100

From Mindat formula

Synonyms

  • Alpha-Duftite
  • α-Duftit
  • α-Duftita

Classification

Strunz
10th ed.

8.BH.35

  • 8Phosphates, Arsenates, VanadatesClass
  • 8.BPhosphates, etc., with additional anions, without H2ODivision
  • 8.BHWith medium-sized and large cations, (OH,etc.):RO4 = 1:1Group
  • 8.BH.35Duftite-alphaSpecies
Dana
8th ed.

41.05.02.05

  • 41Anhydrous Phosphates, Etc.containing Hydroxyl or HalogenClass
  • 41.05(AB)2(XO4)ZqType
  • 41.05.02Descloizite GroupGroup
  • 41.05.02.05Duftite-alphaSpecies

Group, growth & confusion

In the same group
16 members
Commonly confused with
1 mineral

Literature, links & citation

Citations
  1. 1956Guillemin, Claude (1956) Contribution à la minéralogie des arséniates, phosphates et vanadates de cuivre. I. — Arséniates de cuivre. Bulletin de Minéralogie, 79 (1) 7-95 doi:10.3406/bulmi.1956.5049DOI: 10.3406/bulmi.1956.5049
Cite this entry
@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Duftite-alpha — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/duftite-alpha-5267},
  note      = {Accessed 2026-05-11}
}